Method of pasteurizing milk or cream.



P En'r OFFICE.

CHARLES E. ROGERS, F DE'TROIT, MICHIGAN.-

I METHOD OF PASTEURIZING MILK OR CREAM.

No Drawing.

Specification of Letters Patent.

Application filed February 8, 1912. Serial No. 676,371.

Patented May 5,1914.

I citizen of the United States, residing at Detroit, county. of Wayne, State of Michigan,

have invented a certain new and useful Improvement in Methods of Pasteurizing Milk or Cream, and declare the following to be a .full, clear, and exact description of the same, such as will enable others skilled in the art to which it pertains to make and use the same.

This invention'relates to .a method of pas teurizing milk or cream and its object is a method of treatment whereby the fluid treated will keep in a sweet and palatable condition for a much longer period of time than is ordinarily attained by the methods at present in use.

Both milk and cream deteriorate rapidly due to the presence and growth of bacteria therein and, as .is well known" in the art, heatingthe fluid and raising its temperature to from 140 degrees to 150 degrees F. practically destroys this germ life andthe fluid will remain sweet for a greater period of time than if not so treated.

At the present time the principal creamcries and milk depots pasteurize the. greater part of the milk and cream received, but the results attained are not entirely satisfactory either to the dealer or the consumer as the product still does not keep-for a" sufficient period of time. This I have found to be due to the rapid development of bacteria in the product after pasteurization, the 'germ content in several samples tested twenty-four hours after treatment generally being. as

high as, and some higher than, 2,000,000 or-.

ganisms per cubic centimeter. Evidently such a-high bacterial count cannot result from the development of the organisms from the spores contained in the product which are not destroyed by the treatment and must, therefore, result from faults arising in the method of treatment. The method generally in use throughout the United States for this purposeis to heat the milk or cream to the desired temperature (substantially 145 degrees F.), immediately cool the fluid by passing it over cold pipesor analogous means, and then bottle the product in bottles at normal temperature, and finally cap the bottles with a paper cap. A variation of this method lately coming into use consists in holding the fluid at the temperature stated for a period of about thirty minutes before cooling, the succeeding steps following in the order and manner stated; The cooling of the fluid is performed while the product is open to the air in the plant and it may, therefore, readily become contaminated. The bottling of the fluid is usually performed in a room ar ranged for such purpose where the fluid is continuously in contact with the bacteria laden air and the bottles are also infected prior to filling due to their remaining in such air while drying and cooling after being cleansed. It is therefore not surprising that milk and cream treatedin this manner after treatment for, although'the germ li c has been destroyed during a portion of the thereinto as soon as the fluid has cooled to such extent that the organisms may exist therein;

By my improved method of treatment the milk or cream cannot become infected from any exterior source until the bottles are uncapped and maybe delivered to the con- 'sumer within a certain time limit in pracmay be accomplished by means of anypf purpose. Obviously this step may be performed with bottles that are not heated as a succeeding step would destroy, such erm becomes infected and deteriorates rapidl teurizing temperature for a period of about bottles or packages with the heated the filling machines at present in use fdr this life as might existin the bottle or pac age,

treatment, bacteria aredirectly introduced but I prefer to heat the bottles and fill them while so heated; thus introducing the fluid into a package that is free of vegetating organisms. I

The third step, that of capping the bottles, may be performed b ap aratus at present in use or by hand i so esired and the preferable cap iis the paper cap now most universally in use for this purpose. While the preferable package is the glass bottleat present in use for the distribution of milk and cream, it is evident that packages of a different nature and form may be utilized for this purpose in which case thfs step would be performed by sealing such packages in the manner usual with the form and ty employed and it is to be understood that this step may be performed in such manner without departing from the spirit of this invention.

The fourth step, that of holding the packaged fluid in a pasteurizing temperature for about thirty minutes, may be accomplished by simply placing the capped or sealed pack ages in a chamber or room having the proper temperature and for the required period of time or it may be accomplished by placing the packaged fluid in water of the required temperature for the required period. One of the faults of the present method of treatment is that the fluid is heated only for a moment. or so and furthermore is not uniformly heated. The germ life existing therein, therefore,-- is"not as completely destroyed as is possible with the degree of temperature employed, but by heatin for a longer period (as has lately been t e practice) the organisms may be as completely destroyed as is possible at the temperature stated. This latter method, however, while effectual at the time of heating, has its effectiveness destroyed by the introduction of 'bacteria therein during and after cooling. It is to overcome these defects in treatment that this step is employed in the manner above outlined and an essential characteristic of the step is that the fluid is packaged and capped or sealed during its per-- perature. of substantially degrees F, and

the packages should remain in the water until the contents thereof are approximately of the same temperature as the water when they should immediately be placed in water having a temperature of substantially 40. degrees F. until the contents of the package is of the same temperature.

The above described process does not require any apparatus other than that which is well known or at present in use for like pur oses and may be readily performed wit out the use of machinery if so desired. However, for the pasteurization of milk or cream on a commercial scale, advantage should be taken of present known apparatus and the arrangement thereof should be such that the labor of handling be reduced to a minimum.

While the method outlined is the prefer- :able one, the first-two steps may be eliminated and replaced by that step which consists in lacing the fluid to be treated in bottles whi e both the fluid and the bottles are 'at normal temperature, the third and succeeding steps next taking place in order. Such variation is possible by reason of the fourth step as out-lined whereby the germ life is effectually destroyed.

. As is well known in the art, pasteurizing milk and cream does not destroy 'all the spores contained. therein for which purpose a much higher degree of temperature would be required than is above stated. Fluid so treated, therefore, will after a certain length of time contain a living organisms which have developed from the spores as well as those which have been introduced thereinto in the manner stated. By my improved method no livin organisms exist in the fluid at the time 1t is ready for delivery to the consumer and none may enter the fluid until the package is opened. Samples treated by my improved method that were tested 24 hours after treatment showed a bacterial content of less than 1000 per cubic centimeter and in a number of instances contained about 600 per cubic centimeter, while,

asabove stated, tests made or milk treated formed, what I claim and desire to secure.

by Letters Patent of the United States is- 1. The herein described method of treating milk or cream which consists in heating the fluid to: substantially 140to 150 degrees F., placing the heated fluid in heated bottles,

cappin the bottles, subjecting the filled and cappe bottles to a temperature of substanheated to substantially the same degree,

capping the bottles, subjecting the filled and capped bottles to a temperature, of substantially 140 to 150 degrees F. for a period of about thirty minutes, and finally cooling'the bottled fluid. 3. The herein described method of treating milk or cream which consists inheating' packages heated to substantially the same degree, sea-ling the packages, and immediately subjecting the packaged fluid to a pasteurizing temperature for a period of about thirty minutes.

5. The herein described method of treating milk or cream, which consists in heating the fluid to substantially 140, to 150' degrees F, placin the fluid while so heated in bottles heate to substantially the same degree,

closing the bottles with a cap or analogous device,subjecting the filled and closed bottles to a temperature of substantially to 140 to 150degrees F. for a period of about 30 minutes, and finally cooling the bottled fluid by immediately placing in water having a temperature of substantially 70 degrees F. until the fluid is of that temperature and then immediately placing the fluid in water having a temperature of substantially 40 degrees 6. In a method of treating milk or cream the steps which consist in heating the fluid to a pasteurizing temperature, packaging the fluid while at a pasteurizin ture, sealing the packages, sub ecting the sealed packages to a pasteurizing temperature for a period of about 30 minutes, and then immediately cooling the packaged 7. In a method of treating milk or cream the steps which consist in heating the fluid to a pasteurizing temperature, placing the fluid while at a pasteurizing temperature in bottles having substantially the same tem-' perature, capping the bottles while at said temperature, continuing the bottles at said temperature for a period of about 30 min utes after capping; and then immediately e cooling the bottled fluid.

tempera- 

